U.S. patent number 5,793,339 [Application Number 08/337,825] was granted by the patent office on 1998-08-11 for visual display apparatus.
This patent grant is currently assigned to Olympus Optical Co., Ltd.. Invention is credited to Koichi Takahashi.
United States Patent |
5,793,339 |
Takahashi |
August 11, 1998 |
Visual display apparatus
Abstract
A compact and lightweight visual display apparatus which enables
observation of an image that is clear throughout the image field at
a field angle of 120.degree. when the user observes with both eyes,
and which has a large exit pupil diameter. The visual display
apparatus has a two-dimensional image display device (6) for
displaying an image for observation, a relay optical system (5) for
projecting a real image of the two-dimensional image display device
(6) in the air, an ocular magnifier (3) for projecting the real
image in the air as an enlarged image and for reflectively bending
an optical axis, and a decentered correcting optical system (4)
disposed between the relay optical system (5) and the ocular
magnifier (3) and having surfaces (41 and 42) decentered with
respect to each other. The decentered correcting optical system (4)
is arranged such that the vertex (43) of the surface (41) which is
closer to the ocular magnifier (3) lies inward of the visual axis
(7) after it has been reflected by the ocular magnifier (3), and
the ocular magnifier-side surface (41) is an aspherical surface
formed from such a curved surface that the refractive power reaches
a maximum in the vicinity of the surface vertex (43) and becomes
weaker as the distance from the vertex (43) increases toward the
outer side. The apparatus may be arranged to correct the diopter by
making at least one optical element movable.
Inventors: |
Takahashi; Koichi (Hachioji,
JP) |
Assignee: |
Olympus Optical Co., Ltd.
(Tokyo, JP)
|
Family
ID: |
26362992 |
Appl.
No.: |
08/337,825 |
Filed: |
November 8, 1994 |
Foreign Application Priority Data
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Nov 11, 1993 [JP] |
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5-282495 |
Feb 23, 1994 [JP] |
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6-025395 |
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Current U.S.
Class: |
345/7;
348/E13.039; 348/E13.041; 359/630 |
Current CPC
Class: |
G02B
17/08 (20130101); G02B 17/0852 (20130101); G02B
27/0172 (20130101); H04N 13/344 (20180501); H04N
13/339 (20180501); G02B 2027/0178 (20130101); G02B
2027/011 (20130101) |
Current International
Class: |
G02B
27/01 (20060101); G02B 17/08 (20060101); H04N
13/00 (20060101); G02B 27/00 (20060101); G09G
005/00 () |
Field of
Search: |
;345/7,8,9 ;340/980
;348/53,115 ;359/630,631,13,728 ;434/44 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
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2-138975 |
|
Nov 1990 |
|
JP |
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5-21208 |
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Feb 1993 |
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JP |
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5-134208 |
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May 1993 |
|
JP |
|
5-241122 |
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Sep 1993 |
|
JP |
|
Primary Examiner: Liang; Regina
Attorney, Agent or Firm: Cushman Darby & Cushman IP
Group of Pillsbury Madison & Sutro LLP
Claims
What we claim is:
1. A visual display apparatus comprising a two-dimensional image
display device for displaying an image for observation, a relay
optical system for projecting a real image of said two-dimensional
image display device in the air, an ocular magnifier for projecting
said real image in the air as an enlarged image and for
reflectively bending an optical axis, and a decentered correcting
optical system disposed between said relay optical system and said
ocular magnifier and having surfaces decentered with respect to
each other,
wherein said decentered correcting optical system is arranged such
that a vertex of the surface thereof which is closer to said ocular
magnifier lies inward of a visual axis after it has been reflected
by said ocular magnifier, and an ocular magnifier-side surface is
an aspherical surface which is formed from such a curved surface
that refractive power reaches a maximum in the vicinity of the
surface vertex and becomes weaker as the distance from the surface
vertex increases toward the outer side.
2. A visual display apparatus according to claim 1, which satisfies
the following condition:
where R.sub.ym is the radius of curvature in a horizontal
cross-section of said ocular magnifier containing the observer's
visual axis when he or she looks straight forward, and E.sub.xp is
the distance from the exit pupil position of said visual display
apparatus to the center of said ocular magnifier in the direction
of the observer's visual axis when he or she looks straight
forward.
3. A visual display apparatus according to claim 1, which satisfies
the following condition:
where .theta..sub.l is the angle of inclination of said ocular
magnifier-side surface of said decentered correcting optical system
with respect to the visual axis after it has been reflected by said
ocular magnifier.
4. A visual display apparatus according to claim 1, wherein said
decentered correcting optical system is relatively thick in wall
thickness in the vicinity of the vertex of said ocular
magnifier-side surface and relatively thin at the outer side
thereof.
5. A visual display apparatus according to claim 1, wherein all
lenses constituting said relay optical system are coaxial with
respect to each other.
6. A visual display apparatus according to claim 1, wherein said
two-dimensional image display device is tilted with respect to a
center axis of said relay optical system.
7. A visual display apparatus according to claim 1, which satisfies
the following condition:
where R.sub.yl is the radius of curvature in a YZ-plane of said
ocular magnifier-side surface of said decentered correcting optical
system, and R.sub.y2 is the radius of curvature in the YZ-plane of
the relay optical system-side surface of said decentered correcting
optical system.
8. A visual display apparatus according to claim 1, wherein either
said ocular magnifier or said decentered correcting optical system
has an anamorphic surface.
9. A visual display apparatus according to claim 1, wherein either
said ocular magnifier or said decentered correcting optical system
has an aspherical surface.
10. A visual display apparatus comprising:
a two-dimensional image display device for displaying an image for
observation;
a relay optical system for projecting a real image of said
two-dimensional image display device in the air;
an ocular magnifier for projecting said real image in the air as an
enlarged image and for reflectively bending an optical axis;
and
a decentered correcting optical system disposed between said relay
optical system and said ocular magnifier and having surfaces
decentered with respect to each other,
wherein at least one lens constituting said relay optical system
moves in a space reserved between said two-dimensional image
display device and said ocular magnifier to correct diopter,
and
wherein even if at least one lens constituting said relay optical
system is moved, there is no change in the distance from the
observer's pupil to said two-dimensional image display device.
11. A visual display apparatus comprising:
a two-dimensional image display device for displaying an image for
observation;
a relay optical system for projecting a real image of said
two-dimensional image display device in the air;
an ocular magnifier for projecting said real image in the air as an
enlarged image and for reflectively bending an optical axis;
and
a decentered correcting optical system disposed between said relay
optical system and said ocular magnifier and having surfaces
decentered with respect to each other,
wherein said decentered correcting optical system moves in a space
reserved between said two-dimensional image display device and said
ocular magnifier to correct diopter, and
wherein even if said decentered correcting optical system is moved,
there is no change in the distance from the observer's pupil to
said two-dimensional image display device.
12. A visual display apparatus comprising:
a two-dimensional image display device for displaying an image for
observation;
a relay optical system for projecting a real image of said
two-dimensional image display device in the air;
an ocular magnifier for projecting said real image in the air as an
enlarged image and for reflectively bending an optical axis;
and
a decentered correcting optical system disposed between said relay
optical system and said ocular magnifier and having surfaces
decentered with respect to each other,
wherein said ocular magnifier is moved to correct diopter, and
wherein even if said ocular magnifier is moved, there is no change
in the distance from the observer's pupil to said two-dimensional
image display device.
13. A visual display apparatus according to any one of claims 1 to
12, which is accommodated in a body of an image display apparatus
and has a support member whereby said image display apparatus body
can be fitted on the observer's face.
14. A visual display apparatus according to claim 13, wherein said
image display apparatus body is further provided with means for
transmitting sound to the observer.
15. A visual display apparatus according to claim 14, wherein said
image display apparatus body further has a reproducing device for
transmitting image and sound signals to said two-dimensional image
display device and said sound transmitting means, respectively.
16. A visual display apparatus according to claim 10, 11, or 12,
which is accommodated in a body of an image display apparatus and
has a support member whereby said image display apparatus body can
be fitted on the observer's face.
17. A visual display apparatus according to claim 10, 11 or 12,
wherein said at least one lens constituting said relay optical
system, or said decentered correcting optical system or said ocular
magnifier moves with an eccentricity from the optical axis.
18. A visual display apparatus according to claim 17, which is
accommodated in a body of an image display apparatus and has a
support member whereby said image display apparatus body can be
fitted on the observer's face.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a visual display apparatus and,
more particularly, to a head- or face-mounted visual display
apparatus that can be retained on the observer's head or face.
Hitherto, display units, e.g., CRT, LCD, etc., for displaying
television or computer images have been demanded to have a wider
display screen and a higher resolution in order to satisfy
observers' desire to enjoy watching even more powerful images in an
even more absorbed state. In recent years, various large-sized
display units have been developed to provide the effect of virtual
reality. These display units are also required to have a wide field
angle and high resolution.
Even with a small-sized display unit, if an image of the display
screen can be observed as an enlarged image, the field angle of
observation becomes large, so that the observation image becomes
powerful and enables the observer to get absorbed in watching it,
and the virtual reality effect can be obtained. Accordingly, a
variety of compact head-mounted visual display apparatuses have
been developed.
As a related art, a head-mounted visual display apparatus that uses
a decentered concave ocular magnifier and a decentered relay
optical system is disclosed in Japanese Patent Application
Laid-Open (KOKAI) No. 05-134208 (1993) by the present applicant.
FIG. 39 is a sectional view of one embodiment of the disclosed
head-mounted visual display apparatus. In the figure, reference
symbols denote elements or portions as follows: P is the center of
rolling of an observer's eyeball 33; C is the observer's visual
axis when he or she looks straight forward; Q.sub.1 is the position
of the observer's pupil; S.sub.8 is a spheroid having O as the
center of revolution; 16 is a reflecting surface of the spheroid;
17 is an optical axis of a relay optical system; Q.sub.2 is the
focal point of the spheroid; 15 is the relay optical system; and 14
is a two-dimensional image display device.
FIG. 40 is a sectional view of one embodiment a prior application
(Japanese Patent Application No. 5-21208 (1993); U.S. patent
application Ser. No. 08/193,858) by the present applicant, which
uses a decentered ocular magnifier, a decentered relay optical
system, and a decentered correcting optical system. In FIG. 40,
reference numeral 22 denotes the position of an observer's pupil,
23 an ocular concave mirror, 24 the observer's visual axis, 28 a
decentered correcting optical system, 34 a two-dimensional image
display device, and 35 a relay optical system.
In a head-mounted visual display apparatus, it is necessary to
ensure a wide field angle in order to enhance the feeling of being
at the actual spot which is given to the observer when viewing the
displayed image. In particular, the stereoscopic effect of the
image presented is determined by the angle at which the image is
presented (see The Journal of the Institute of Television Engineers
of Japan Vol. 45, No. 12, pp. 1589-1596 (1991)).
It is known that it is necessary in order to present an absorbing,
stereoscopic and powerful image to the observer to ensure a field
angle of 40.degree. (.+-.20.degree.) or more in the horizontal
direction, and that the stereoscopic and other effects are
saturated in the vicinity of 120.degree. (.+-.60.degree.). In other
words, it is preferable to select a field angle for observation
which is not smaller than 40.degree. and which is as close to
120.degree. as possible.
Further, to give the observer the feeling of being at the actual
spot when viewing the displayed image and also the virtual reality
effect, it is essential for a visual display apparatus to have a
wide field angle and high resolution and to provide as large a
pupil diameter as possible in a case where the exit pupil of the
optical system lies at the observer's pupil position so that the
visual field is not eclipsed by the rolling movement of the eye
when the user tries to observe a peripheral region of the image
field.
However, it has heretofore been impossible with the conventional
technique to realize a high-resolution visual display apparatus
that provides a wide field angle of 120.degree. when the user
observes with both eyes, as described above.
Further, when a decentered magnifier is used as an ocular optical
system in a head-mounted visual display apparatus as described
above, the distance from the observer's pupil position to the
ocular optical system is preferably not shorter than 30 mm, which
is a spacing at which no mechanical interference occurs around the
observer's eye and at which the observer feels no sensation of
pressure when wearing this visual display apparatus. On the other
hand, to realize a wide field angle and high resolution with a
compact structure, the distance from the observer's pupil position
to the ocular optical system should preferably be shortened as much
as possible. The angle between the visual axis immediately behind
the observer's pupil and the visual axis after it has been
reflected by the ocular optical system must be 40.degree. or more
in order to avoid interference between the visual display apparatus
and the observers' face or head, but on the other hand, aberration
produced by the optical system reduces as the above-described angle
decreases.
In the case of a visual display apparatus that uses an ocular
optical system having the above-described conditions, it is
expected to some extent that spectacles which the observer is
wearing will interfere with the optical system or block the optical
path. Therefore, there may be cases where it is difficult for the
user to observe an electronic image of a two-dimensional image
display device with his/her spectacles on. Accordingly, it is
important to correct the diopter of the visual display apparatus in
conformity to the observer's visual acuity. However, no diopter
correction method has heretofore been realized for a visual display
apparatus that provides a wide field angle and high resolution and
that has a relatively complicated optical system arrangement, which
is composed of an ocular optical system, a decentered correcting
optical system, a relay optical system, and a two-dimensional image
display device, as shown above in connection with the description
of the related art.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above-described
problems of the background art, and it is a first object of the
present invention to provide a compact and lightweight visual
display apparatus which enables observation of an image that is
clear throughout the image field at a field angle of 120.degree.
when the user observes with both eyes, and which has a large exit
pupil diameter.
It is a second object of the present invention to provide a visual
display apparatus which enables diopter correction to be realized
simply by moving at least one of optical elements constituting an
optical system of the apparatus, that is, an ocular optical system,
a decentered correcting optical system, a relay optical system, and
a two-dimensional image display device.
To attain the above-described objects, the present invention
provides a visual display apparatus having a two-dimensional image
display device for displaying an image for observation, a relay
optical system for projecting a real image of the two-dimensional
image display device in the air, an ocular magnifier for projecting
the real image in the air as an enlarged image and for reflectively
bending an optical axis, and a decentered correcting optical system
disposed between the relay optical system and the ocular magnifier
and having surfaces decentered with respect to each other. The
decentered correcting optical system is arranged such that the
vertex of a surface thereof which is closer to the ocular magnifier
lies inward of a visual axis after it has been reflected by the
ocular magnifier, and the ocular magnifier-side surface is an
aspherical surface which is formed from such a curved surface that
the refractive power reaches a maximum in the vicinity of the
surface vertex and becomes weaker as the distance from the surface
vertex increases toward the outer side.
In this case, it is preferable to satisfy the following
condition:
where R.sub.ym is the radius of curvature in a horizontal
cross-section of the ocular magnifier containing the observer's
visual axis when he or she looks straight forward, and E.sub.xp is
the distance from the exit pupil position of the visual display
apparatus to the center of the ocular magnifier in the direction of
the observer's visual axis when he or she looks straight
forward.
Further, it is preferable to satisfy the following condition:
where .theta..sub.1 is the angle of inclination of the ocular
magnifier-side surface of the decentered correcting optical system
with respect to the visual axis after it has been reflected by the
ocular magnifier.
Further, it is preferable to arrange the decentered correcting
optical system such that it is relatively thick in wall thickness
in the vicinity of the vertex of the ocular magnifier-side surface
and relatively thin at the outer side thereof.
Further, it is preferable that all lenses constituting the relay
optical system should be coaxial with respect to each other.
The two-dimensional image display device may be tilted with respect
to the center axis of the relay optical system.
Further, it is preferable to satisfy the following condition:
where R.sub.yl is the radius of curvature in a YZ-plane of the
ocular magnifier-side surface of the decentered correcting optical
system, and R.sub.y2 is the radius of curvature in the YZ-plane of
the relay optical system-side surface of the decentered correcting
optical system.
Further, either the ocular magnifier or the decentered correcting
optical system may have an anamorphic surface.
Further, either the ocular magnifier or the decentered correcting
optical system may have an aspherical surface.
In addition, the present invention provides a visual display
apparatus having a two-dimensional image display device for
displaying an image for observation, a relay optical system for
projecting a real image of the two-dimensional image display device
in the air, an ocular magnifier for projecting the real image in
the air as an enlarged image and for reflectively bending an
optical axis, and a decentered correcting optical system disposed
between the relay optical system and the ocular magnifier and
having surfaces decentered with respect to each other. At least one
of the following optical elements, that is, the screen of the
two-dimensional image display device, an optical surface of the
relay optical system, an optical surface of the decentered
correcting optical system, and the ocular magnifier, is movably
provided so that the diopter can be corrected.
In this case, the at least one movable optical element may be any
one or more of the optical elements: the screen of the
two-dimensional image display device, an optical surface of the
relay optical system, an optical surface of the decentered
correcting optical system, and the ocular magnifier.
The visual display apparatus may be arranged such that even if the
at least one movable optical element is moved, there is no change
in the distance from the observer's pupil to the two-dimensional
image display device.
The at least one movable optical element may move with an
eccentricity from the optical axis.
It should be noted that the present invention includes an
arrangement in which any of the above-described visual display
apparatuses is accommodated in the body of an image display
apparatus and has a support member whereby the image display
apparatus body can be fitted on the observer's face.
In this case, the image display apparatus body may be further
provided with a device for transmitting sound to the observer. The
image display apparatus body may further have a reproducing device
for transmitting image and sound signals to the two-dimensional
image display device and the sound transmitting device,
respectively.
The reason for adopting the above-described arrangements and the
functions thereof will be explained below.
The general arrangement of the apparatus according to the present
invention will be explained with reference to FIG. 1. FIG. 1 is an
illustration of the visual display apparatus of the present
invention fitted for the observer's right eye as viewed from above
the observer. The optical arrangement is illustrated by backward
tracing in which light rays are traced from the observer's pupil 1
toward the two-dimensional image display device 6 for the
convenience of description. In FIG. 1, reference numeral 1 denotes
an observer's pupil, 8 an observer's eyeball, 2 the observer's
visual axis when he or she looks straight forward, 12 the
observer's nose, and 13 an observer's ear. The visual display
apparatus of the present invention is composed of a two-dimensional
image display device 6 for displaying an image for observation, a
relay optical system 5 for projecting a real image of the
two-dimensional image display device 6 in the air, an ocular
magnifier 3 for projecting the real image in the air as an enlarged
image and for bending an optical axis, and a decentered correcting
optical system 4 disposed between the relay optical system 5 and
the ocular magnifier 3 and having surfaces decentered with respect
to each other.
The vertex 43 of the ocular magnifier-side surface (first surface)
41 of the decentered correcting optical system 4 lies inward of
(closer to the nose than) the visual axis 7 after it has been
reflected by the ocular magnifier 3, and the first surface 41 is an
aspherical surface which has such a curved surface configuration
that the power is strongest in the vicinity of the vertex 43 and
becomes weaker as the distance from the vertex 43 increases toward
the outer side (the ear side).
The reason for adopting such an arrangement and the function
thereof will be explained below. First, how the decentered
correcting optical system 4 contributes to the formation of a pupil
image will be explained. In the following description of the
present invention, a coordinate system is defined as follows: The
horizontal direction of the observer is taken as Y-axis, where the
leftward direction is defined as positive direction; the direction
of the observer's visual axis 2 is taken as Z-axis, where the
direction toward the ocular magnifier 3 from the observer's eyeball
8 is defined as positive direction; and the vertical direction of
the observer is taken as X-axis, where the downward direction is
defined as positive direction. FIG. 2 illustrates a pupil ray trace
in the YZ-plane of the apparatus shown in FIG. 1. In the figure,
reference numeral 1 denotes a pupil position, 3 an ocular
magnifier, 4 a decentered correcting optical system, 5 a relay
optical system, 45 a position where a pupil image is formed, 51
inner pupil rays, and 52 outer pupil rays.
Formation of a pupil image by the inner rays (i.e., rays closer to
the nose) 51 in the YZ-plane will be explained below. FIG.3(a)
illustrates a trace of the inner pupil rays 51 in the YZ-plane when
the rays 51 pass via only the ocular magnifier 3. FIG. 3(b)
illustrates a trace of the inner pupil rays 51 in the YZ-plane when
the rays 51 pass via both the ocular magnifier 3 and the decentered
correcting optical system 4. FIGS. 4(a) and 4(b) similarly
illustrate pupil ray traces in the XZ-plane. However, it should be
noted that the reflecting surface in FIGS. 4(a) and 4(b) is not
coincident with the sectional reflecting surface because the rays
are reflected in an off-axis manner, and the ocular magnifier 3 and
the decentered correcting optical system 4 are each decentered.
Further, since each decentered optical element and the optical axis
are projected on the XZ-plane, the pupil conjugate position and the
optical path length are different from those of the actual
system.
As will be clear from FIG. 3(a), since the inner rays 51 emanating
from the pupil 1 are immediately reflected by the ocular magnifier
3, the reflected pupil rays 51 form an image at a relatively
distant position 46 (46') [see FIGS. 3(a) and 4(a)]. Therefore, in
order to form a pupil image at the pupil conjugate position 45,
which is in the relay optical system 5 at a side thereof which is
closer to the ocular magnifier 3, the decentered correcting optical
system 4 must have a positive power in both the YZ- and XZ-planes
[see FIGS. 3(b) and 4(b)].
Next, the outer pupil rays (i.e., rays closer to the ear) 52 in the
YZ-plane will be explained with reference to FIGS. 5(a) and 5(b),
which illustrate a pupil ray trace in the YZ-plane in the same way
as in FIGS. 3(a) and 3(b) for the inner pupil rays 51, and with
reference to FIGS. 6(a) and 6(b), which illustrate a pupil ray
trace in the XZ-plane in the same way as in FIGS. 4(a) and 4(b) for
the inner pupil rays 51.
The outer rays 52 emanating from the pupil 1 are reflected by the
ocular magnifier 3 and form an image at a relatively near position
47 (47') [see FIGS. 5(a) and 6(a)] because the distance from the
pupil 1 to the point on the ocular magnifier 3 where the rays 52
are reflected is relatively long. That is, in order to form a pupil
image at the pupil conjugate position 45 in the relay optical
system 5 at a side thereof which is closer to the ocular magnifier
3, the decentered correcting optical system 4 must have either an
exceedingly weak positive power or a negative power in both the YZ-
and XZ-planes [see FIGS. 5(b) and 6(b)].
To satisfy these conditions, it is essential to dispose the vertex
43 of the first surface 41 in the vicinity of the visual axis 7 in
the YZ-plane. If the vertex 43 of the first surface 41 of the
decentered correcting optical system 4 lies closer to the ear, it
is difficult to allow the decentered correcting optical system 4 to
have a weak positive power or a negative power in the vicinity of
the outer most portion thereof while maintaining a wedge shape,
which is an important condition imposed on the decentered
correcting optical system 4 (described later). The arrangement in
which the vertex 43 of the first surface 41 lies closer to the nose
than the visual axis 7 makes it easy to increase the power of the
inner side of the decentered correcting optical system 4. Further,
in order to form the decentered correcting optical system 4 so that
the wall thickness thereof decreases as the distance from the
vertex 43 increases toward the outer side and the outermost portion
has a weak positive power or a negative power, it is essential to
arrange the decentered correcting optical system 4 so that the
first surface 41 is an aspherical surface formed from such a curved
surface that the curvature is the strongest at the center and
becomes weaker as the distance from the center increases toward the
periphery thereof.
In the present invention, an image surface formed by the ocular
magnifier 3, which is disposed in a decentered position, has
relatively large inclination and curvature. The inner image is
formed at a position closer to the ocular magnifier 3, while the
outer image is formed at a position closer to the relay optical
system 5. Therefore, an effective way of correcting the inclination
of the image surface is to form the decentered correcting optical
system 4 such that the inner side thereof is relatively thick in
terms of wall thickness, while the outer side thereof is relatively
thin. With such a wedge-shaped lens, the optical path length can be
made asymmetrical according to the field angle. Thus, the image 10
formed by the ocular magnifier 3 can be effectively placed to lie
in a direction perpendicular to the center axis 9 of the relay
optical system 5. However, since the field angle is wide, the
corrected image surface 11 cannot completely be made perpendicular
to the center axis 9. Therefore, in order to correct the
inclination of the image surface 11, it is even more preferable to
tilt the two-dimensional image display device 6 with respect to the
center axis 9 of the relay optical system 5.
Further, it is preferable that the second surface 42 of the
decentered correcting optical system 4 should have a concave
surface directed toward the relay optical system 5. If the second
surface 42 is formed from a curved surface directed in the same
direction as the curved first image surface, the optical path
length becomes relatively long in the vicinity of the optical axis
and relatively short at the peripheries. Accordingly, this
arrangement is also effective in correcting the curvature of
field.
The relationship between the ocular magnifier 3 and the exit pupil
position 1 is concerned with the pupil image formation and
influences the overall size of the apparatus. Accordingly, it is
preferable to satisfy the following condition:
where R.sub.ym is the radius of curvature in the YZ-plane of the
ocular magnifier 3, and E.sub.xp is the distance from the position
of the exit pupil 1 to the center of the ocular magnifier 3 in the
direction of the Z-axis.
If .vertline.R.sub.ym /E.sub.xp .vertline.is not larger than the
lower limit of the condition (1), i.e., 1.3, the ray height at the
decentered correcting optical system 4 reduces, resulting in a
reduction in the aberration correcting effect by the optical system
4. If .vertline.R.sub.ym /E.sub.xp .vertline. is not smaller than
the upper limit of the condition (1), i.e., 2.6, the position 45
conjugate to the pupil 1 shifts from the position in the relay
optical system 5 that is closer to the two-dimensional image
display device 6 to a position which is closer to the ocular
magnifier 3, resulting in an increase in the size of the relay
optical system 5.
Further, it is preferable to satisfy the following condition:
where .theta..sub.1 is the angle of inclination in the YZ-plane of
the first surface 41 of the decentered correcting optical system 4
with respect to the optical axis 7 (the counterclockwise direction
is defined as positive direction).
The condition (2) must be satisfied in order to change the
inclination of the center axis of the first surface 41 of the
decentered correcting optical system 4 so that the center axis of
the first surface 41 lies in the same direction as the visual axis
7 after it has been reflected by the ocular magnifier 3. If
.theta..sub.1 is not larger than the lower limit of the condition
(2), i.e., if the vertex 43 of the first surface 41 lies 10.degree.
or more outward of the visual axis 7 after it has been reflected by
the ocular magnifier 3, the curvature center of the first surface
41 is disposed at the outer side, resulting in an increase in the
wall thickness of the outer side of the decentered correcting
optical system 4. Accordingly, it becomes impossible to
satisfactorily correct the inclination and curvature of the image
surface at the outer side of the image field. If .theta..sub.1 is
not smaller than the upper limit of the condition (2), i.e.,
30.degree., the decentered correcting optical system 4 undesirably
projects toward the nose, resulting in an increase in the size, and
giving rise to the problem that the optical system may interfere
with the observer's face.
Further, it is preferable that the power ratio of the surfaces of
the decentered correcting optical system 4 should be set within the
following range as a condition to be satisfied in order to correct
aberrations in the whole optical system:
where R.sub.yl is the radius of curvature in the YZ-plane of the
ocular magnifier-side surface (first surface) 41 of the decentered
correcting optical system 4, and R.sub.y2 is the radius of
curvature in the YZ-plane of the relay optical system-side surface
(second surface) 42 of the decentered correcting optical system
4.
The condition (3) expresses the power in the YZ-plane of the
decentered correcting optical system 4 and is an important
condition for correcting the inclination and curvature of the image
surface formed by the ocular magnifier 3. Since the surfaces
constituting the decentered correcting optical system 4 are
decentered, it is impossible to strictly define the power of this
optical element. However, if R.sub.yl /R.sub.y2 is not larger than
the lower limit of the condition (3), i.e., 0.4, the power
difference between the first surface 41 and the second surface 42
becomes large, causing higher-order coma and astigmatism to
increase to such an extent that the aberrations cannot be corrected
by other optical system. If R.sub.yl /R.sub.y2 is not smaller than
the upper limit of the condition (3), i.e., 1.2, it is impossible
to obtain asymmetry required to correct the inclination and
curvature of the image surface over the whole image field. If it is
intended to correct the inclination of the image surface by
decentering of the relay optical system 5 and to correct the
curvature by the field curvature of the relay optical system 5,
then the relay optical system 5 is heavily loaded, and this causes
the relay optical system 5 to become large in size and complicated
in arrangement in cooperation with the increase in the pupil
diameter.
Further, since the ocular magnifier 3 is decentered with respect to
the optical axis, astigmatism which is not rotationally symmetric
with respect to the optical axis occurs. Particularly, there is a
large difference between the sagittal and meridional image
surfaces. To correct the astigmatism, it is preferable that either
the ocular magnifier 3 or the decentered correcting optical system
4 should have an anamorphic surface. To realize high resolution as
far as the edges of the image field, it is preferable that the
surface of the ocular magnifier 3 and the surfaces of the
decentered correcting optical system 4 should be aspherical
surfaces.
Further, it is preferable that all the lenses of the relay optical
system 5 should be disposed coaxially with respect to each other.
If all the lenses of the relay optical system 5 are coaxial with
respect to each other, the relay optical system 5 can be loaded in
an ordinary lens barrel. Thus, it is possible to facilitate the
production and assembly of the constituent elements of the
apparatus.
As has been described above, it is possible to realize a visual
display apparatus which satisfies the demand for high resolution
while ensuring a wide field angle for observation and a large pupil
diameter by using an optical system composed of the decentered
ocular magnifier 3, the decentered correcting optical system 4
having two surfaces decentered with respect to each other, in which
the first surface 41 is formed from an aspherical surface having
the vertex 43 at a position closer to the observer's nose, and the
relay optical system 5, which is compact in size and relatively
simple in arrangement.
Next, the reason for adopting the above-described arrangement to
attain the second object of the present invention and the function
thereof will be explained on the basis of the principle of the
arrangement.
FIG. 15 illustrates an optical ray trace of the optical system of
the visual display apparatus (Example 5, described later) according
to the present invention. As shown in FIG. 15, the optical system
is composed of a two-dimensional image display device 6 for
displaying an image for observation, a relay optical system 5 for
projecting a real image of the two-dimensional image display device
6 in the air, an ocular magnifier 3 for projecting the real image
in the air as an enlarged image, and a decentered correcting
optical system 4 disposed between the relay optical system 5 and
the two-dimensional image display device 6 and having surfaces
decentered with respect to each other. The decentered correcting
optical system 4 is provided to correct the inclination and
curvature of an image surface formed by the ocular magnifier 3,
which is decentered with respect to the visual axis 7 after it has
been reflected by the ocular magnifier 3, and to tilt the optical
axis.
Incidentally, diopter correction may be effected by a diopter
correcting lens or the like which is inserted in the optical path.
However, it is difficult to adopt this method for a visual display
apparatus having the above-described arrangement. It is impossible
to insert anything but a contact lens in the space between the
observer's pupil 1 and the ocular magnifier 3. Nothing can be
inserted in the space between the ocular magnifier 3 and the
decentered correcting optical system 4 because rays pass in all
directions in this space. There is no spatial room between the
decentered correcting optical system 4 and the relay optical system
5 and also between the relay optical system 5 and the
two-dimensional image display device 6. On the contrary, if a room
for inserting a diopter correcting element is provided in either
space, the apparatus undesirably becomes large in size and
complicated in arrangement.
Accordingly, if the apparatus is arranged such that the power
distribution to the whole optical system can be changed so as to
effect diopter correction simply by moving any one of the optical
elements basically constituting the optical system, value added can
be attached to the visual display apparatus at low cost without
increasing the overall size of the apparatus.
Next, the behavior of rays when an optical element having power,
which is a diopter correcting element of the visual display
apparatus of the present invention that has a diopter correcting
function, is moved will be explained by employing the paraxial
theory using a thin lens. FIG. 14 illustrates a paraxial ray trace
through a thin lens. It is assumed that the focal length of the
thin lens L is f, and the power thereof is .PHI.. As shown in FIG.
14, the object point P and the image point P' are conjugate to each
other, and it is assumed that the distances from the lens L to the
object and image points P and P' are s (which is minus in the
illustrated example) and s', respectively, the inclinations of the
paraxial ray at the object and image points P and P' are u (which
is minus in the illustrated example) and u', respectively, and the
ray height at the lens L is h. In this case, fundamental
expressions of image formation are as follows:
The ray when the lens L is moved toward the object point side by
As, for example, is shown by the broken line in FIG. 14. It is
assumed that as a result of the movement of the lens L, the ray
height lowers by ah, the inclination at the image point side
becomes u", and the distance from the lens L to the image point
becomes S". Regarding the inclination, since h in equation (4)
becomes h-.DELTA.h, u" is expressed by
Since h>0, .DELTA.h>0, and .PHI.>0, the following
expression may be said to be valid by comparison of equations (4)
and (6):
Regarding the distance from the lens L to the image point, on the
other hand, since s in equation (5) becomes s-.DELTA.s, s" is
expressed by
Since s<0 and .DELTA.s<0, the following expression may be
said to be valid by comparison of equations (5) and (8):
It may be considered that the ray height, inclination and so forth
change with the movement of each optical element on the basis of
equations (4) and (5) in the same way as in the above-described
example.
Next, how a standard of the amount of movement of a diopter
correcting element is determined according to the amount of diopter
correction will be explained by taking a relay optical system as an
example. It is assumed that the focal length of the entire optical
system is f.sub.a, the distance from the object-side focal point to
the object point is z (which is minus in the illustrated example),
and the distance from the image-side focal point to the image point
is z'. In FIG. 14, the relationship between f.sub.a and z is shown
with the lens L regarded as the entire optical system of the visual
display apparatus according to the present invention. The
expression of image formation based on the focal points is given
by
Assuming that the focal length of the relay optical system is
f.sub.l, and the magnification of other optical element is .beta.,
f.sub.a is expressed by
Diopter D, which indicates dioptic power, is expressed by
Let us assume that the relay optical system is a diopter correcting
element, and the amount of movement for correction is .DELTA.z.
With z in equation (10) replaced by .DELTA.z, equation (10) may be
rearranged according to equations (11) and (12) as follows:
Therefore, to effect diopter correction for -2diopters, for
example, under the conditions that f.sub.l =30 mm, and .beta.=0.7,
the relay optical system should be moved toward the image side by
about 0.9 mm.
Next, the power distribution to the entire optical system of the
visual display apparatus according to the present invention will be
described, together with a diopter correcting method for
nearsightedness and farsightedness.
FIG. 8 shows the power distribution to the entire optical system
and also illustrates a paraxial ray trace. In the figure, reference
numeral 1 denotes a pupil, 3 an ocular reflecting optical system, 4
a decentered correcting optical system, 5 a relay optical system, 6
a two-dimensional image display device (object surface), 20 a real
image formed by the relay optical system 5, 21 an object paraxial
ray, and 27 a pupil paraxial ray. For the sake of description, the
rays are traced backward from the pupil 1 toward the
two-dimensional image display device 6.
In the case of nearsightedness, the refractive power of the
crystalline lens in the eyeball is too strong, so that only an
image of a near object can be formed on the retina. Therefore, rays
which behave as if they had a positive refractive power at the
pupil must be formed by an optical system. In the case of
farsightedness, conversely, rays which behave as if they had a
negative refractive power at the pupil must be formed. FIG. 9
illustrates a ray trace in the case of nearsightedness. FIG. 10
illustrates a ray trace in the case of farsightedness. As will be
clear from FIGS. 9 and 10, in the case of nearsightedness, the
object position 61 lies closer to the pupil 1 than in the case of
the normal eyesight, while, in the case of farsightedness, the
object position 62 lies remoter from the pupil 1 than in the case
of the normal eyesight. Diopter correction is an operation of
matching the displaced object position 61 or 62 with the object
position 60 in the case of the normal eyesight, where the
two-dimensional image display device 6 lies, by moving an element
of the optical system.
The following description of diopter correction will be made for
nearsightedness only. This is because it may be considered that
diopter correction for farsightedness is usually effected by
movement reverse to that in the case of nearsightedness with regard
to the paraxial rays.
FIG. 11 illustrates a ray trace when the ocular optical system 3 is
used as a diopter correcting element. In the figure, the ray trace
before the diopter correction is shown by the solid line 25, and
the ray trace after the correction is shown by the dotted line 26.
It should be noted that the position of each element after the
corrective movement is described by putting the symbol ' or " to
the reference numeral. As shown in the figure, the movement of the
ocular optical system 3 away from the pupil 1 causes an increase in
the distance between the pupil 1 and the ocular optical system 3
and also in the distance between the decentered correcting optical
system 4 and the ocular optical system 3. The ray height at the
ocular optical system 3 lowers, and the angle of refraction
decreases. The decentered correcting optical system 4 shifts to 4'.
Since the angle of incidence is small, the angle of refraction
decreases. The position of the following relay optical system 5
shifts to 5', and the position of the two-dimensional image display
device 6 shifts to 6', but there is no change in the power
distribution. Accordingly, the object position coincides with the
previous object position 6' (see FIG. 9) as shown by the dotted
line 26 in the figure.
FIG. 12 illustrates a ray trace when the decentered correcting
optical system 4 is used as a diopter correcting element. The
arrangement in the figure is the same as that in FIG. 11. As shown
in FIG. 12, movement of the decentered correcting optical system 4
to a position 4" closer to the pupil 1 causes the real image
position to come closer to the decentered correcting optical system
4, and the ray height lowers. Accordingly, the angle of refraction
decreases, and the object position can be shifted to a position
away from the pupil 1.
FIG. 13 illustrates a ray trace when the relay optical system 5 is
used as a diopter correcting element. As shown in the figure,
movement of the relay optical system 5 to a position 5" closer to
the pupil 1 causes the refraction position to come closer to the
real image 20 (see FIGS. 8 to 10). Accordingly, the angle of
refraction decreases, and the object position can be shifted to a
position away from the pupil 1. Diopter correction can also be
effected by moving the lenses of the relay optical system 5 in
combination or alone. Movement of a certain lens of the relay
optical system 5 causes the position of the principal point of the
relay optical system 5 to change. Thus, the object position can be
moved so as to effect diopter correction.
It will be clear that when the two-dimensional image display device
6 is used as a diopter correcting element, the two-dimensional
image display device 6 should be moved to either of the object
positions 61 and 62 according to whether the user is nearsighted or
farsighted, as shown in FIGS. 9 and 10. That is, when the user is
nearsighted, the two-dimensional image display device 6 is moved to
the object position 61, which is formed at a position closer to the
pupil 1, whereas, when the user is farsighted, the two-dimensional
image display device 6 is moved to the object position 62, which is
formed at a position away from the pupil 1.
Diopter correction can also be effected by combining together the
above-described diopter correcting elements, as a matter of course.
In a case where the field angle for observation is wide and each
optical element is decentered, the paraxial theory is often
inapplicable to the circumstances. Therefore, the amount of
aberration produced in the optical system may increase unless a
plurality of diopter correcting elements are used in combination.
In a case where each optical element is disposed in a decentered
position, the diopter correcting element should preferably move
eccentrically with a view to effectively suppressing the occurrence
of aberrations.
If diopter correction can be effected by moving only the diopter
correcting element without changing the distance from the pupil 1
to the two-dimensional image display device 6, there is no change
in the overall size of the apparatus. Accordingly, the external
appearance of the apparatus is simple, and the movable portion for
diopter correction can be made compact. Therefore, such an
arrangement is even more preferable.
Still other objects and advantages of the invention will in part be
obvious and will in part be apparent from the specification.
The invention accordingly comprises the features of construction,
combinations of elements, and arrangement of parts which will be
exemplified in the construction hereinafter set forth, and the
scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view for explanation of the general arrangement of the
visual display apparatus according to the present invention.
FIG. 2 illustrates a pupil ray trace in a horizontal plane of the
apparatus shown in FIG. 1.
FIGS. 3(a) and 3(b) illustrate a trace of the inner pupil rays in
the horizontal plane.
FIGS. 4(a) and 4(b) illustrate a trace of the inner pupil rays in
the vertical plane.
FIGS. 5(a) and 5(b) illustrate a trace of the outer pupil rays in
the horizontal plane.
FIGS. 6(a) and 6(b) illustrate a trace of the outer pupil rays in
the vertical plane.
FIGS. 7(a), 7(b) and 7(c) are views for explanation of a method of
setting a field angle for observation.
FIG. 8 shows power distribution to the entire optical system of the
visual display apparatus according to the present invention and
also illustrates a paraxial ray trace.
FIG. 9 illustrates a paraxial ray trace in the case of
nearsightedness.
FIG. 10 illustrates a paraxial ray trace in the case of
farsightedness.
FIG. 11 illustrates a paraxial ray trace when an ocular optical
system is used as a diopter correcting element.
FIG. 12 illustrates a paraxial ray trace when a decentered
correcting optical system is used as a diopter correcting
element.
FIG. 13 illustrates a paraxial ray trace when a relay optical
system is used as a diopter correcting element.
FIG. 14 is a view for explanation of the behavior of rays when an
optical element having power is moved.
FIG. 15 illustrates an optical ray trace of the optical system of
the visual display apparatus according to the present
invention.
FIG. 16 is a horizontal sectional view showing the optical
arrangement of Example 1 of the present invention.
FIG. 17 is a part of a spot diagram showing the condition of
aberration correction in Example 1.
FIG. 18 is another part of the spot diagram showing the condition
of aberration correction in Example 1.
FIG. 19 is the other part of the spot diagram showing the condition
of aberration correction in Example 1.
FIG. 20 is a horizontal sectional view showing the optical
arrangement of Example 2 of the present invention.
FIG. 21 is a horizontal sectional view showing the optical
arrangement of Example 3 of the present invention.
FIG. 22 is a horizontal sectional view showing the optical
arrangement of Example 4 of the present invention.
FIG. 23 is a horizontal sectional view showing the optical
arrangement of Example 5 of the present invention.
FIG. 24 is a horizontal sectional view showing the optical
arrangement of Example 6 of the present invention.
FIG. 25 is a horizontal sectional view showing the optical
arrangement of Example 7 of the present invention at 0 diopter.
FIG. 26 is a horizontal sectional view showing the optical
arrangement of Example 7 at -3 diopters.
FIG. 27 is a horizontal sectional view showing the optical
arrangement of Example 7 at -6 diopters.
FIG. 28 is a horizontal sectional view showing the optical
arrangement of Example 7 at +2 diopters.
FIG. 29 is a horizontal sectional view showing the optical
arrangement of Example 8 of the present invention.
FIG. 30 is a horizontal sectional view showing the optical
arrangement of Example 9 of the present invention at 0 diopter.
FIG. 31 is a horizontal sectional view showing the optical
arrangement of Example 9 at -6 diopters.
FIG. 32 is a horizontal sectional view showing the optical
arrangement of Example 10 of the present invention.
FIG. 33 is a horizontal sectional view showing the optical
arrangement of Example 11 of the present invention.
FIG. 34 is a horizontal sectional view showing the optical
arrangement of Example 12 of the present invention.
FIG. 35 is a sectional view of one head-mounted visual display
apparatus that employs the visual display apparatus of the present
invention.
FIG. 36 shows one example of the mode of using the head-mounted
visual display apparatus arranged as shown in FIG. 35.
FIG. 37 shows another example of the mode of using the head-mounted
visual display apparatus arranged as shown in FIG. 35.
FIGS. 38(a) and 38(b) show other examples of the mode of using the
head-mounted visual display apparatus arranged as shown in FIG.
35.
FIG. 39 shows the arrangement of one head-mounted visual display
apparatus proposed by the present applicant.
FIG. 40 shows the arrangement of another head-mounted visual
display apparatus proposed by the present applicant.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The visual display apparatus of the present invention will be
described below by way of some examples. A coordinate system is
defined as follows: With the observer's pupil 1 defined as the
origin, the horizontal direction of the observer is taken as
Y-axis, where the leftward direction is defined as positive
direction; the direction of the observer's visual axis 2 is taken
as Z-axis, where the direction toward the ocular magnifier 3 from
the observer's eyeball 8 is defined as positive direction; and the
vertical direction of the observer is taken as X-axis, where the
downward direction is defined as positive direction.
Next, a method of setting a field angle for observation will be
explained with reference to FIGS. 7(a). 7(b) and 7(c). FIG. 7(a)
shows the field angle for right-eyed vision; FIG. 7(b) shows the
field angle for left-eyed vision; and FIG. 7(c) shows the field
angle for binocular vision. As shown in these figures, the
horizontal field angle for right-eyed vision is set extending over
from +25.degree. to -60.degree., for example, and the hatched
region extending over from -25.degree. to +25.degree. is defined as
a binocular fusion region where images viewed with the left and
right eyes fuse into a single image. A region extending over from
-25.degree. to -60.degree. is set so as to be recognized with only
one eye as an ear-side peripheral image. Since the performance of
the optical system in the vertical direction is symmetrical with
respect to the Y-axis, only an upper-half field angle of
33.75.degree. is set. In other words, although the horizontal field
angle is set extending over from +25.degree. to -60.degree. for one
eye, in binocular vision it is recognized as an observation field
angle of 120.degree.. The vertical field angle is simply double the
set field angle 33.75.degree., that is, 67.5.degree..
The following examples are visual display apparatuses for the right
eye. A visual display apparatus for the left eye can be realized by
disposing the constituent optical elements of each example in
symmetrical relation to the apparatus for the right eye with
respect to the XZ-plane.
In the figures showing the examples, reference numeral 1 denotes
the position of the observer's pupil, 3 an ocular magnifier, 4 a
decentered correcting optical system, 5 a relay optical system, and
6 a two-dimensional image display device. In the figures showing
Examples 1 to 4, reference numeral 2 denotes the observer's visual
axis when he or she looks straight forward, and 7 the visual axis
after it has been reflected by the ocular magnifier 3.
The following Examples 1 to 12 satisfy the conditions of the first
aspect of the present invention.
FIG. 15 shows the arrangement of the optical system of Example 1.
The surface of the ocular magnifier 3 and the surfaces of the
decentered correcting optical system 4 are anamorphic aspherical
surfaces. The relay optical system 5 is composed of 5 spherical
lenses arranged in 4 lens units.
In this example, the horizontal field angle is 120.degree., while
the vertical field angle is 67.5.degree., and the pupil diameter is
10 mm.
FIGS. 17 to 19 are spot diagrams showing the condition of
aberration correction made in this example. In these figures, among
four numerals on the left-hand side of the spot diagram, the upper
two numerals represent coordinates (X, Y) when the coordinates (X,
Y) of a rectangular image plane are expressed as follows: The
coordinates of the center of the image plane are (0.00, 0.00); the
coordinates of the center of the right-hand edge thereof are (0.00,
-1.00); the coordinates of the top right corner thereof are (1.00,
-1.00); and the coordinates of the center of the top edge thereof
are (1.00, 0.00). The lower two numerals represent X- and
Y-components (expressed by degrees) of angle made by the coordinate
axes (X, Y) with respect to the visual axis (the center of the
image plane).
FIG. 20 shows the arrangement of the optical system of. Example 2.
The arrangement of Example 2 is the same as that of Example 1
except that the relay optical system 5 is composed of 6 lenses
arranged in 4 lens units.
In the above-described example, the horizontal field angle is
120.degree., while the vertical field angle is 67.5.degree., and
the pupil diameter is 10 mm.
FIG. 21 shows the arrangement of the optical system of Example 3.
The arrangement of Example 3 is the same as that of Example 1
except that the relay optical system 5 is composed of 6 lenses
arranged in 4 lens units.
In the above-described example, the horizontal field angle is
120.degree., while the vertical field angle is 67.5.degree., and
the pupil diameter is 10 mm.
FIG. 22 shows the arrangement of the optical system of Example 4.
The arrangement of Example 4 is the same as that of Example 1
except that the ocular magnifier 3 has a toric surface, and that
the first surface of the decentered correcting optical system 4 is
an anamorphic surface, while the second surface is a spherical
surface, and further that the relay optical system 5 is composed of
6 lenses arranged in 4 lens units.
In the above-described example, the horizontal field angle is
120.degree., while the vertical field angle is 67.5.degree., and
the pupil diameter is 10 mm.
Examples 5 to 12, which mainly relate to diopter correction, will
be explained below. It should be noted that description of the
field angle is omitted.
FIG. 23 shows the arrangement of the optical system of Example 5.
In the figure, the solid lines show the layout of the optical
system at 0 diopter, and the dotted lines show the layout of the
optical system at -6 diopters. Ray tracing is made by solid lines
for both cases. In this example, the ocular magnifier 3 alone
serves as a diopter correcting element. The ocular magnifier 3
moves in the YZ-plane according to diopter, thereby effecting
diopter correction. In the case of nearsightedness, the ocular
magnifier 3 moves so that the distance from the pupil 1 shortens
(Z: minus), and also moves upward (Y: plus) as viewed in the
figure. In the case of farsightedness, the ocular magnifier 3 moves
reversely for both Z and Y.
In this example, diopter correction can also be effectively made by
moving the ocular magnifier 3 in only the Z direction as a diopter
correcting element.
FIG. 24 shows the arrangement of the optical system of Example 6.
In the figure, the solid lines show the layout of the optical
system at 0 diopter, and the dotted lines show the layout of the
optical system at -6 diopters. Ray tracing is made by solid lines
for both cases. In this example, the decentered correcting optical
system 4 alone serves as a diopter correcting element. The
decentered correcting optical system 4 moves in the YZ-plane,
thereby effecting diopter correction. In the case of
nearsightedness, the decentered correcting optical system 4 moves
toward the ocular magnifier 3 (Z: plus), and also moves downward
(Y: minus) as viewed in the figure. In the case of farsightedness,
the decentered correcting optical system 4 moves reversely for both
Z and Y. In other words, diopter correction can be effected by
tilting the decentered correcting optical system 4 about a certain
point.
FIGS. 25 to 27 show the arrangement of the optical system of
Example 7. FIG. 25 shows the layout of the optical system at 0
diopter; FIG. 26 shows the layout at -3 diopters; FIG. 27 shows the
layout at -6 diopters; and FIG. 28 shows the layout at +2 diopters.
In these figures are shown only a ray on the visual axis and rays
which pass through the edge of the pupil 1 and reach a point on the
two-dimensional image display device 6 that is on the visual axis.
In this example, the decentered correcting optical system 4, the
relay optical system 5 and the two-dimensional image display device
6 serve as diopter correcting elements. Diopter correction is
effected by simultaneously moving these optical elements. In the
case of nearsightedness (FIGS. 26 and 27), the decentered
correcting optical system 4, the relay optical system 5 and the
two-dimensional image display device 6 move toward the ocular
magnifier 3 (Z: plus) and also move upward (Y: plus). In the case
of farsightedness, these optical elements move reversely for both Z
and Y.
In Example 7, diopter correction can also be effected by moving the
decentered correcting optical system 4, the relay optical system 5
and the two-dimensional image display device 6 in parallel along
the optical axis of the relay optical system 5.
FIG. 29 shows the arrangement of the optical system of Example 8.
In the figure, the solid lines show the layout of the optical
system at 0 diopter, and the dotted lines show the layout of the
optical system at -6 diopters. Ray tracing is made by solid lines
for both cases. In this example, the first lens of the relay
optical system 5 alone serves as a diopter correcting element. The
first lens moves in an off-axis manner according to diopter,
thereby effecting diopter correction. However, there is no change
in the overall length of the optical system. In the case of
nearsightedness, the first lens moves toward the two-dimensional
image display device 6 (Z: plus), and also moves upward (Y: plus)
as viewed in the figure. In the case of farsightedness, the first
lens moves reversely for both Z and Y.
FIGS. 30 and 31 show the arrangement of the optical system of
Example 9. FIG. 30 shows the layout of the optical system at 0
diopter, and FIG. 31 shows the layout of the optical system at -6
diopters. In these figures are shown only a ray on the visual axis
and rays which pass through the edge of the pupil 1 and reach a
point on the two-dimensional image display device 6 that is on the
visual axis. In this example, the whole relay optical system 5
serves as a diopter correcting element. The whole relay optical
system 5 moves along the center axis of the relay optical system 5
in the YZ-plane without changing any spacing in the relay optical
system 5, thereby effecting diopter correction. In the case of
nearsightedness (FIG. 31), the whole relay optical system 5 moves
toward the ocular magnifier 3 (Z: plus) and also move upward (Y:
plus) as viewed in the figure. In the case of farsightedness, the
whole relay optical system 5 moves reversely for both Z and Y.
FIG. 32 shows the arrangement of the optical system of Example 10.
In the figure, the solid lines show the layout of the optical
system at 0 diopter, and the dotted lines show the layout of the
optical system at -6 diopters. Ray tracing is made by solid lines
for both cases. In this example, only the second to fifth lenses of
the relay optical system 5 serve as diopter correcting elements.
The second to fifth lenses move in parallel along the center axis
of the relay optical system 5, thereby effecting diopter
correction. However, there is no change in the overall length of
the optical system. In the case of nearsightedness, the second to
fifth lenses move toward the two-dimensional image display device 6
as viewed in the figure, whereas, in the case of farsightedness,
the second to fifth lenses move in the opposite direction to the
above.
FIG. 33 shows the arrangement of the optical system of Example 11.
In the figure, the solid lines show the layout of the optical
system at 0 diopter, and the dotted lines show the layout of the
optical system at -6 diopters. Ray tracing is made by solid lines
for both cases. In this example, only the second and third lenses,
which are cemented together, in the relay optical system 5 serve as
a diopter correcting element. The cemented lens move along the
center axis of the relay optical system 5, thereby effecting
diopter correction. However, there is no change in the overall
length of the optical system. In the case of nearsightedness, the
cemented lens moves toward the two-dimensional image display device
6 as viewed in the figure, whereas, in the case of farsightedness,
the cemented lens moves in the opposite direction to the above.
FIG. 34 shows the arrangement of the optical system of Example 12.
In the figure, the solid lines show the layout of the optical
system at 0 diopter, and the dotted lines show the layout of the
optical system at -6 diopters. Ray tracing is made by solid lines
for both cases. In this example, only the two-dimensional image
display device 6 serves as a diopter correcting element. The
two-dimensional image display device 6 moves eccentrically to
thereby effect diopter correction. In the case of nearsightedness,
the two-dimensional image display device 6 moves so that the
distance from the relay optical system 5 to the two-dimensional
image display device 6 shortens and in such a manner as to rotate
clockwise (A: minus). In the case of farsightedness, the
two-dimensional image display device 6 moves so that the distance
from the relay optical system 5 to the two-dimensional image
display device 6 lengthens and in such a manner as to rotate
counterclockwise (A: plus).
In Example 12, diopter correction can also be effected by moving
the two-dimensional image display device 6 in a direction parallel
to the refracted optical axis exiting from the relay optical system
5.
Constituent parameters of each example will be shown below. It
should be noted that the surface Nos. are shown as ordinal numbers
in backward tracing from the observer's iris position 1 toward the
two-dimensional image display device 6.
As to the amount of decentration (eccentricity) and the tilt angle
(inclination angle) in the constituent parameters, the ocular
magnifier 3 is given eccentricities in the Y- and Z-axis
directions. The eccentricity in the Y-axis direction is a distance
by which the vertex of the ocular magnifier 3 decenters in the
Y-axis direction from the visual axis (Z-axis direction) passing
through the center of the exit pupil 1. The eccentricity in the
Z-axis direction is a distance by which the vertex of the ocular
magnifier 3 decenters in the Z-axis direction from a reference
position given by the surface separation. The decentered correcting
optical system 4 is given an eccentricity of the vertex of each of
the surfaces from the center of the exit pupil 1 in each of the Y-
and Z-axis positive directions, and an angle of inclination of the
center axis passing through the vertex of each surface with respect
to the Z-axis. The inclination angle of the center axis of each
surface is given with the angle of rotation from the axis of the
positive direction of the Z-axis toward the axis of the positive
direction of the Y-axis (in the counterclockwise direction as
viewed in the figure) defined as angle in the positive direction.
Regarding the relay optical system 5, the vertex position of the
first surface thereof is given in the same way as in the case of
each surface of the decentered correcting optical system 4. A
center axis that passes through the vertex of the first surface is
an optical axis, and the angle of inclination of this optical axis
is given in the same way as the above. With regard to the
two-dimensional image display device 6, a coordinate system is
defined as follows: The optical axis of the relay optical system 5
is taken as Z-axis, where the direction toward the ocular magnifier
3 from the two-dimensional image display device 6 is defined as
positive direction; an axis that perpendicularly intersects the
Z-axis in the plane of the figure is taken as Y-axis, where the
leftward direction of the two-dimensional image display device 6 is
defined as positive direction; and an axis normal to the plane of
the figure is taken as X-axis, where the downward direction is
defined as positive direction. The two-dimensional image display
device 6 is given an eccentricity as a distance by which the center
thereof shifts in the Y-axis positive direction in the coordinate
system, and an angle of inclination of the normal to the surface
thereof with respect to the Z-axis.
The non-rotationally symmetric aspherical configuration of each
surface of the ocular magnifier 3 and the decentered correcting
optical system 4 may be expressed by.
where R.sub.y is the paraxial curvature radius of each surface in
the YZ-plane (the plane of the figure); R.sub.x is the paraxial
curvature radius in the XZ-plane; K.sub.x is the conical
coefficient in the X-direction; K.sub.y is the conical coefficient
in the Y-direction; AR and BR are rotationally symmetric 4th- and
6th-order aspherical coefficients, respectively; and AP and BP are
asymmetric 4th- and 6th-order aspherical coefficients,
respectively.
Regarding the surface separation, the spacing between the exit
pupil 1 and the ocular magnifier 3 is shown as a distance in the
Z-axis direction, and the spacing between the first surface of the
relay optical system 5 and the image surface thereof (the
two-dimensional image display device 6) is shown as a distance
along the optical axis thereof. As to the relay optical system 5,
the radii of curvature of the surfaces are denoted by r.sub.l, to
r.sub.i, the surface separations by d.sub.1 to d.sub.i, the
refractive indices for the spectral d-line by n.sub.l to n.sub.i,
and the Abbe's numbers by .nu..sub.1 to .nu..sub.i. It should be
noted that the refractive index for the spectral d-line of the
medium of the decentered correcting optical system 4 is denoted by
n, and the Abbe's number thereof by .nu..
In Examples 5 to 12, the diopter of the basic design is 0 diopter.
Amounts of diopter correction are -6 diopters, -3 diopters, and +2
diopters. As the amount of movement of the diopter correcting
element, the surface separation or eccentricity or inclination
angle corresponding to each amount of diopter correction are shown
in order.
______________________________________ Example 1 Refractive Abbe's
No. Surface Radius of Surface index (Inclination No. curvature
separation (Eccentricity) angle)
______________________________________ 1 (1) .infin.(pupil) 52.937
2 (3) R.sub.y -70.986 0 Y: -30.399 A: 0.000.degree. R.sub.x -55.670
Z: 0.000 K.sub.y -0.135913 K.sub.x 0.016895 AR 0.165065 .times.
10.sup.-6 BR -0.357359 .times. 10.sup.-10 AP -1.10375 BP -1.38177 3
(4) R.sub.y -13.310 0 n = 1.492410 .nu. = 57.7 R.sub.x -25.812 Y:
-24.295 A: 57.353.degree. K.sub.y -1.238838 Z: 5.491 K.sub.x
-1.338735 AR -0.457589 .times. 10.sup.-5 BR -0.696261 .times.
10.sup.-10 AP -1.80420 BP -1.91510 4 R.sub.y -22.873 0 Y: -54.239
A: 25.312.degree. R.sub.x -38.381 Z: 10.878 K.sub.y -0.219669
K.sub.x 6.895198 AR -0.13467 .times. 10.sup.-4 BR -0.811146 .times.
10.sup.-10 AP -0.214307 BP 4.23122 5 (r.sub.1) -54.563 (d.sub.1)
-12.012 n.sub.1 = 1.65518 .nu..sub.1 = 54.2 Y: -59.457 A:
29.819.degree. Z: -8.794 6 (r.sub.2) 37.853 (d.sub.2) -10.295 7
(r.sub.3) -48.164 (d.sub.3) -9.954 n.sub.2 = 1.60958 .nu..sub.2 =
60.8 8 (r.sub.4) 17.835 (d.sub.4) -1 n.sub.3 = 1.75500 .nu..sub.3 =
27.6 9 (r.sub.5) 115.840 (d.sub.5) -1 10 (r.sub.6) -61.279
(d.sub.6) -7.098 n.sub.4 = 1.51922 .nu..sub.4 = 67.2 11 (r.sub.7)
68.453 (d.sub.7) -0.5 12 (r.sub.8) -26.153 (d.sub.8) -10.534
n.sub.5 = 1.60007 .nu..sub.5 = 61.4 13 (r.sub.9) -232.494 (d.sub.9)
-8.705 14 (6) .infin.(image) Y: -2.387 A: 18.330.degree. (1)
.vertline.R.sub.ym /Exp .vertline. = 1.34 (2) .theta..sub.1 =
17.35.degree. (3) R.sub.y1 /R.sub.y2 = 0.58
______________________________________ Example 2 Refractive Abbe's
No. Surface Radius of Surface index (Inclination No. curvature
separation (Eccentricity) angle)
______________________________________ 1 (1) .infin.(pupil) 53.193
2 (3) R.sub.y -73.925 0 Y: -31.587 A: 0.000.degree. R.sub.x -56.047
Z: 0.000 K.sub.y -0.121576 K.sub.x -0.002027 AR 0 BR 0 AP 0 3 (4)
R.sub.y -17.937 0 n = 1.620000 .nu. = 60.3 R.sub.x -39.743 Y:
-26.565 A: 64.820.degree. K.sub.y -0.864551 Z: 3.376 K.sub.x
1.244101 AR 0 BR 0 AP 0 BP 0 4 R.sub.y -22.713 0 Y: -47.798 A:
47.700.degree. R.sub.x -22.032 Z: 8.592 K.sub.y -0.467511 K.sub.x
0.697794 AR 0 BR 0 AP 0 BP 0 5 (r.sub.1) -47.696 (d.sub.1) -19.179
n.sub.1 = 1.62189 .nu..sub.1 = 59.9 Y: -59 607 A: 29.495.degree. Z:
-5.653 6 (r.sub.2) 37.907 (d.sub.2) -8.797 7 (r.sub.3) -41.178
(d.sub.3) -7.459 n.sub.2 = 1.57325 .nu..sub.2 = 63.0 8 (r.sub.4)
18.809 (d.sub.4) -1 n.sub.3 = 1.75500 .nu..sub.3 = 27.6 9 (r.sub.5)
98.492 (d.sub.5) -4.484 10 (r.sub.6) -47.373 (d.sub.6) -7.908
n.sub.4 = 1.62000 .nu..sub.4 = 60.3 11 (r.sub.7) 99.015 (d.sub.7)
-0.1 12 (r.sub.8) -25.681 (d.sub.8 ) -13.617 n.sub.5 = 1.62000
.nu..sub.5 = 60.3 13 (r.sub.9) 67.228 (d.sub.9) -1 n.sub.6 =
1.75500 .nu..sub.6 = 27.6 14 (r.sub.10) -280.298 (d.sub.10) -5.255
15 (6) .infin.(image) Y: -3.444 A: 15.880.degree. (1) R.sub.ym
/E.sub.xp .vertline. = 1.39 (2) .theta..sub.1 = 24.82.degree. (3)
R.sub.y1 /R.sub.y2 = 0.79 ______________________________________
Example 3 Refractive Abbe's No. Surface Radius of Surface index
(Inclination No. curvature separation (Eccentricity) angle)
______________________________________ 1 (1) .infin.(pupil) 53.111
2 (3) R.sub.y -74.090 0 Y: -31.367 A: 0.000.degree. R.sub.x -57.656
Z: 0.000 K.sub.y -0.019788 K.sub.x 0.052441 AR 0 BR 0 AP 0 BP 0 3
(4) R.sub.y -18.246 0 n = 1.57802 .nu. = 62.7 R.sub.x -43.172 Y:
-27.076 A: 54.715.degree. K.sub.y -1.142012 Z: 6.016 K.sub.x
1.561471 AR 0 BR 0 AP 0 BP 0 4 R.sub.y -24.911 0 Y: -49.319 A:
33.687.degree. R.sub.x -31.173 Z: 5.162 K.sub.y -0.127403 K.sub.x
2.912338 AR 0 BR 0 AP 0 BP 0 5 (r.sub.1) -39.173 (d.sub.1) -9.020
n.sub.1 = 1.75000 .nu..sub.1 = 25.0 Y: -58.382 A: 33.687.degree. Z:
-5.795 6 (r.sub.2) -17.289 (d.sub.2) -11.270 n.sub.2 = 1.70000
.nu..sub.2 = 35.0 7 (r.sub.3) 39.426 (d.sub.3) -3.284 8 (r.sub.4)
-40.170 (d.sub.4) -8.804 n.sub.3 = 1.62000
.nu..sub.3 = 60.3 9 (r.sub.5) 16.227 (d.sub.5) -1 n.sub.4 = 1.75500
.nu..sub.4 = 27.6 10 (r.sub.6) 80.847 (d.sub.6) -4.432 11 (r.sub.7)
-48.678 (d.sub.7) -8.248 n.sub.5 = 1.62000 .nu..sub.5 = 60.3 12
(r.sub.8) 65.536 (d.sub.8) -0.221 13 (r.sub.9) -25.065 (d.sub.9)
-9.852 n.sub.6 = 1.71554 .nu..sub.6 = 47.1 14 (r.sub.10) -70.239
(d.sub.10) -4.792 15 (6) .infin.(image) Y: -1.482 A: 15.041.degree.
(1) R.sub.ym /E.sub.xp .vertline. = 1.40 (2) .theta..sub.1 =
14.71.degree. (3) R.sub.y1 /R.sub.y2 = 0.73
______________________________________ Example 4 Refractive Abbe's
No. Surface Radius of Surface index (Inclination No. curvature
separation (Eccentricity) angle)
______________________________________ 1 (1) .infin.(pupil) 53.274
2 (3) R.sub.y -73.049 0 Y: -30.301 A: 0.000.degree. R.sub.x -57.175
Z: 0.000 3 (4) R.sub.x -17.366 0 n = 1.52955 .nu. = 66.2 R.sub.x
-30.921 Y: -25.702 A: 61.081.degree. K.sub.y -0.807948 Z: 4.397
K.sub.x 0 AR 0 BR 0 AP 0 BP 0 4 -22.473 0 Y: -46.740 A:
46.460.degree. Z: 4.511 5 (r.sub.1) -43.557 (d.sub.1) -14.786
n.sub.1 = 1.75500 .nu..sub.1 = 27.6 Y: -56.346 A: 34.010.degree. Z:
-5.506 6 (r.sub.2) -25.022 (d.sub.2) -7.163 n.sub.2 = 1.74185
.nu..sub.2 = 44.9 7 (r.sub.3) 44.490 (d.sub.3) -1.059 8 (r.sub.4)
-39.357 (d.sub.4) -11.045 n.sub.3 = 1.59962 .nu..sub.3 = 61.4 9
(r.sub.5) 14.667 (d.sub.5) -1.880 n.sub.4 = 1.75500 .nu..sub.4 =
27.6 10 (r.sub.6) 54.956 (d.sub.6) -4.503 11 (r.sub.7) -49.367
(d.sub.7) -7.723 n.sub.5 = 1.73584 .nu..sub.5 = 45.4 12 (r.sub.8)
67.508 (d.sub.8) -0.487 13 (r.sub.9) -24.369 (d.sub.9) -8.229
n.sub.6 = 1.67363 .nu..sub.6 = 51.7 14 (r.sub.10) -47.303
(d.sub.10) -5.210 15 (6) .infin.(image) Y: -1.469 A: 14.501.degree.
(1) R.sub.ym /E.sub.xp .vertline. = 1.37 (2) .theta..sub.1 =
21.08.degree. (3) R.sub.y1 /R.sub.y2 = 0.77
______________________________________ Example 5 Refractive Abbe's
No. Surface Radius of Surface index (Inclination No. curvature
separation (Eccentricity) angle)
______________________________________ 1 (1) .infin.(pupil) 53.085
2 (3) R.sub.y -73.261 0.000 Y: -31.020 A: 0.000.degree. R.sub.x
-57.4666 Z: 0.000 K.sub.y 0.042534 K.sub.x 0.158972 AR 0.194999
.times. 10.sup.-6 BR -0.121401 .times. 10.sup.-10 AP -0.716898 BP
-1.87289 Amount of Diopter Correction 0 D -3 D -6 D +2 D Y: -31.020
-30.836 -30.898 -31.056 Z: 0.000 -1.627 -3.651 1.165 3 (4) R.sub.y
-13.488 0.000 n = 1.48700 .nu. = 70.4 R.sub.x -34.244 Y: -29.708 A:
51.600.degree. K.sub.y -1.881629 Z: 4.659 K.sub.x -1.761358 AR
-0.330456 .times. 10.sup.-5 BR 0.305923 .times. 10.sup.-13 AP
-1.90466 BP 0.189389 .times. 10.sup.+2 4 R.sub.x -24.745 0.000 Y:
-53.649 A: 27.011.degree. R.sub.x -48.961 Z: 9.443 K.sub.y
-0.433533 8.516905 AR -0.188793 .times. 10.sup.-4 BR -0.254236
.times. 10.sup.-8 AP -0.364870 BP 1.26182 5 (r.sub.1) -75.875
(d.sub.1) -13.313 n.sub.1 = 1.65506 .nu..sub.1 = 54.2 Y: -62.441 A:
28.541.degree. Z: -11.132 6 (r.sub.2) 47.757 (d.sub.2) -6.630 7
(r.sub.3) -43.357 (d.sub.3) -14.180 n.sub.2 = 1.60730 .nu..sub.2 =
61.0 8 (r.sub.4) 14.881 (d.sub.4) -1.768 n.sub.3 = 1.75500
.nu..sub.3 = 27.6 9 (r.sub.5) 77.898 (d.sub.5) -1.922 10 (r.sub.6)
-60.167 (d.sub.6) -6.740 n.sub.4 = 1.52422 .nu..sub.4 = 66.7 11
(r.sub.7) 45.128 (d.sub.7) -0.500 12 (r.sub.8) -26.477 (d.sub.8)
-8.783 n.sub.5 = 1.64862 .nu..sub.5 = 55.2 13 (r.sub.9) 542.733
(d.sub.9) -8.575 14 (6) .infin.(image) Y: -3.299 A: 20.069.degree.
(1) R.sub.ym /E.sub.xp .vertline. = 1.38 (2) .theta..sub.1 =
11.60.degree. (3) R.sub.y /R.sub.y2 = 0.55
______________________________________ Example 6 Refractive Abbe's
No. Surface Radius of Surface index (Inclination No. curvature
separation (Eccentricity) angle)
______________________________________ 1 (1) .infin.(pupil) 53.076
2 (3) R.sub.y -73.399 0.000 Y: -31.160 A: 0.000.degree. R.sub.x
-55.786 Z: 0.000 K.sub.y 0.025030 K.sub.x 0.105299 AR 0.192134
.times. 10.sup.-6 BR -0.845925 .times. 10.sup.-11 AP -0.679221 BP
-1.99742 3 (4) R.sub. -13.871 0.000 n = 1.48757 .nu. = 70.4 R.sub.x
-50.632 Y: -30.520 A: 52.349.degree. K.sub.y -1.760226 Z: 5.033
K.sub.x -1.980652 AR -0.327338 .times. 10.sup.-5 BR 0.168168
.times. 10.sup.-14 AP -1.85576 BP 0.184379 .times. 10.sup.+2 Amount
of Diopter Correction 0 D -3 D -6 D +2 D Y: -30.520 -31.203 -32.056
-29.810 Z: 5.033 6.051 6.586 4.973 4 R.sub.x -26.601 0.000 Y:
-54.878 A: 30.078.degree. R.sub.x -46.355 Z: 9.483
K.sub.y -0.323741 K.sub.x 9.225767 AR -0.171300 .times. 10.sup.-4
BR -0.225926 .times. 10.sup.-8 AP -0.280508 BP 1.21717 Amount of
Diopter Correction 0 D -3 D -6 D +2 D Y: -54.878 -55.561 -56.414
-54.168 Z: 9.483 10.501 11.037 9.424 5 (r.sub.1) -127.947 (d.sub.1)
-15.585 n.sub.1 = 1.65610 .nu..sub.1 = 51.4 Y: -62.930 A:
23.299.degree. Z: -11.047 6 (r.sub.2) 38.998 (d.sub.2) -7.840 7
(r.sub.3) -41.886 (d.sub.3) -11.552 n.sub.2 = 1.60813 .nu..sub.2 =
60.9 8 (r.sub.4) 15.524 (d.sub.4) -1.024 n.sub.4 = -1.75500
.nu..sub.3 = 27.6 9 (r.sub.5) 115.961 (d.sub.5) -2.833 10 (r.sub.6)
-46.408 (d.sub.6) -6.991 n.sub.4 = 1.538969 .nu..sub.4 = 65.5 11
(r.sub.7) 54.373 (d.sub.7) -0.100 12 (r.sub.8) -22.182 (d.sub.8)
-8.670 n.sub.5 = 1.67345 .nu..sub.5 = 51.7 13 (r.sub.9) -286.952
(d.sub.9) -8.108 14 (6) .infin.(image) Y: -4.107 A: 17.591.degree.
(1) .vertline.R.sub.ym /E.sub.xp .vertline. = 1.38 (2)
.theta..sub.1 = 12.35.degree. (3) R.sub.y1 /R.sub.y2 = 0.52
______________________________________ Example 7 Refractive Abbe's
No. Surface Radius of Surface index (Inclination No. curvature
separation (Eccentricity) angle)
______________________________________ 1 (1) .infin.(pupil) 52.110
2 (3) R.sub.y -73.386 0.000 Y: -30.399 A: 0.000.degree. R.sub.x
-57.821 Z: 0.000 K.sub.y -0.013413 K.sub.x 0.187077 AR 0.211715
.times. 10.sup.-6 BR -0.123706 .times. 10.sup.-10 AP -0.699451 BP
-1.87248 3 (4) R.sub.y -13.448 0.000 n = 1.49557 .nu. = 68.1
R.sub.x -33.307 Y: -29.775 A: 51.842.degree. K.sub.y -1.812411 Z:
3.756 K.sub.x -1.78282 AR -0.333342 .times. 10.sup.-5 BR 0.172171
.times. 10.sup.-10 AP -1.88807 BP 0.245019 .times. 10.sup.-2 Amount
of Diopter Correction 0 D -3 D -6 D +2 D Y: -29.775 -28.894 -28.444
-31.073 Z: 3.756 6.369 7.904 2.578 4 R.sub.y -24.579 0.000 Y:
-54.132 A: 27.011.degree. R.sub.x -48.534 Z: 8.204 K.sub.y
-0.454147 K.sub.x 8.753754 AR -0.173802 .times. 10.sup.-4 BR
-0.221562 .times. 10.sup.-10 AP -0.363497 BP 1.21388 Amount of
Diopter Correction 0 D -3 D -6 D +2 D Y: -54.132 -53.251 -52.802
-55.431 Z: 8.204 10.820 12.355 7.028 5 (r.sub.1) -74.068 (d.sub.1)
-12.780 n.sub.1 = 1.65830 .nu..sub.1 = 53.4 Y: -63.115 A:
28.141.degree. Z: -12.357 Amount of Diopter Correction 0 D -3 D -6
D +2 D Y: -63.115 -62.234 -61.785 -64.414 Z: -12.357 -9.741 -8.206
13.533 6 (r.sub.2) 48.464 (d.sub.2) -6.953 7 (r.sub.3) -43.580
(d.sub.3) -14.638 n.sub.2 2= 1.60673 .nu..sub.2 = 61.0 8 (r.sub.4)
14.806 (d.sub.4 ) -1.090 n.sub.3 = 1.75500 .nu..sub.3 = 27.6 9
(r.sub.5) 77.638 (d.sub.5) -1.930 10 (r.sub.6) -57.886 (d.sub.6)
-6.840 n.sub.4 = 1.52095 .nu..sub.4 = 67.0 11 (r.sub.7) 47.786
(d.sub.7) -0.500 12 (r.sub.8) -26.205 (d.sub.8) -8.790 n.sub.6 =
1.64407 .nu..sub.5 = 55.9 13 (r.sub.8) 633.324 (d.sub.9) -8.587 14
(6) .infin.(image) Y: -3.335 A: 20.331.degree. (1)
.vertline.R.sub.ym /E.sub.xp .vertline. = 1.41 (2) .theta..sub.1 =
11.84.degree. (3) R.sub.y1 /R.sub.y2 = 0.55
______________________________________ Example 8 Refractive Abbe's
No. Surface Radius of Surface index (Inclination No. curvature
separation (Eccentricity) angle)
______________________________________ 1 (1) .infin.(pupil) 50.101
2 (3) R.sub.x -73.598 0.000 Y: -31.260 A: 0.000.degree. R.sub.x
-56.177 Z: 0.000 K.sub.y 0.016637 K.sub.x 0.032646 AR 0.139699
.times. 10.sup.-6 BR -0.317892 .times. 10.sup.-11 AP -0.657673 BP
-2.44464 3 (4) R.sub.x -13.756 0.000 n = 1.487000 .nu. = 70.4
R.sub.x -34.115 Y: -29.353 A: 54.266.degree. K.sub.y -1.632557 Z:
6.699 K.sub.x -2.108747 AR -0.290348 .times. 10.sup.-5 BR 0.255039
.times. 10.sup.-13 AP -1.92215 BP 0.188898 .times.10.sup.+2 4
R.sub.y -26.430 0.000 Y: -53.886 A: 30.281.degree. R.sub.x -48.040
Z: 10.034 K.sub.y -0.313689 K.sub.x 9.414019 AR -0.175022 .times.
10.sup.-4 BR -0.244922 .times. 10.sup.-8 AP -0.14822 BP 1.11464 5
(r.sub.1) -108.846 (d.sub.1) -13.314 n.sub.1 = 1.65830 .nu..sub.1 =
53.4 Y: -60.686 A: 23.279.degree. Z: -11.426 Amount of Diopter
Correction 0 D -3 D -6 D +2 D Y: -60.686 -60.916 -60.231 -60.688 Z:
-11.426 -9.596 -8.022 -12.485 A: 23.279.degree. 23.317.degree.
23.141.degree. 22.974.degree. 6 (r.sub.2) 43.058 (d.sub.2) -0.100 7
(r.sub.3) -42.178 (d.sub.3) -15.611 n.sub.2 = 1.60862 .nu..sub.2 =
60.9 8 (r.sub.4) 16.393 (d.sub.4) -1.000 n.sub.3 = 1.75500
.nu..sub.3 = 27.6 9 (r.sub.5) 86.440 (d.sub.5) -1.840 10 (r.sub.6)
-46.337 (d.sub.6) -7.033 n.sub.4 = 1.53277 .nu..sub.4 = 66.0 11
(r.sub.7) 57.156 (d.sub.7) -0.500 12 (r.sub.8)
-23.786 (d.sub.8) -8.478 n.sub.5 = 1.60729 .nu..sub.5 = 59.4 13
(r.sub.9) .infin. (d.sub.9) -8.124 14 (6) .infin.(image) Y: -4.261
A: 20.851.degree. (1) .vertline.R.sub.ym /E.sub.xp .vertline. =
1.47 (2) .theta..sub.1 = 14.27.degree. (3) R.sub.y1 /R.sub.y2 =
0.52 ______________________________________ Example 9 Refractive
Abbe's No. Surface Radius of Surface index (Inclination No.
curvature separation (Eccentricity) angle)
______________________________________ 1 (1) .infin.(pupil) 53.097
2 (3) R.sub.y -73.663 0.000 Y: -31.260 A: 0.000.degree. R.sub.x
-57.403 Z: 0.000 K.sub.y 0.013905 K.sub.x 0.161335 AR 0.198843
.times. 10.sup.-6 BR -0.121967 .times. 10.sup.-10 AP -0.7245 BP
-1.82362 3 (4) R.sub.x -13.710 0.000 n = 1.48727 .nu. = 70.4
R.sub.x -35.716 Y: -29.254 A: 51.817.degree. K.sub.y -1.815291 Z:
5.283 K.sub.x -2.465664 AR -0.317435 .times. 10.sup.-5 BR 0.762415
.times. 10.sup.-14 AP -1.92706 BP 0.326050 .times. 10.sup.+2 4
-25.618 0.000 Y: -53.360 A: 28.030.degree. K.sub. -48.338 Z: 9.244
K.sub.y -0.277791 K.sub.x 9.212224 AR -0.189344 .times. 10.sup.-4
BR -0.269312 .times. 10.sup.-8 AP -0.249264 BP 1.118061 5 (r.sub.1)
-88.343 (d.sub.) -13.657 n.sub.1 = 1.65283 .nu..sub.1 = 54.6 Y:
-63.000 A: 27.694.degree. Z: -11.353 Amount of Diopter Correction 0
D -3 D -6 D +2 D Y: -63.000 -61.983 -60.790 -63.790 Z: -11.353
-9.207 -7.127 -12.508 6 (r.sub.2) 44.464 (d.sub.2) -6.464 7
(r.sub.3) -42.982 (d.sub.3) -13.850 n.sub.2 = 1.60668 .nu..sub.2 =
61.0 8 (r.sub.4) 14.998 (d.sub.4) -1.659 n = 1.75500 .nu..sub.3 =
27.6 9 (r.sub.5) 80.629 (d.sub.5) -1.906 10 (r.sub.6) -55.103
(d.sub.6) -7.029 n.sub.4 = 1.52606 .nu..sub.4 = 66.5 11 (r.sub.7)
49.694 (d.sub.7) -0.500 12 (r.sub.8) -25.903 (d.sub.8) -8.681
n.sub.5 1.65437 .nu..sub.5 = 54.3 13 (r.sub.9) 465.261 (d.sub.9)
-8.482 14 (6) .infin.(image) Y: -3.757 A: 19.959.degree. (1)
.vertline.R.sub.ym /E.sub.xp .vertline. = 1.39 (2) .theta..sub.1 =
11.82.degree. (3) R.sub.y1 /R.sub.y2 = 0.54
______________________________________ Example 10 Refractive Abbe's
No. Surface Radius of Surface index (Inclination No. curvature
separation (Eccentricity) angle)
______________________________________ 1 (1) .infin.(pupil) 53.100
2 (3) R.sub.y -73.606 0.000 Y: -31.260 A: 0.000.degree. R.sub.x
-57.661 Z: 0.000 K.sub.y 0.015884 K.sub.x 0.170305 AR 0.209773
.times. 10.sup.-6 BR -0.123045 .times. 10.sup.-10 AP -0.712283 BP
-1.87849 3 (4) R.sub.y -13.519 0.000 n = 1.499128 .nu. = 66.9
R.sub.x -32.574 Y: -28.940 A: 52.275.degree. K.sub.y -1.762494 Z:
5.282 K.sub.x -1.699031 AR -0.339816 .times. 10.sup.-5 BR 0.350594
.times. 10.sup.-13 AP -1.92936 BP 0.187523 .times. 10.sup.+2 4
R.sub.y -24.789 0.000 Y: -53.723 A: 27.023.degree. R.sub.x -48.321
Z: 9.562 K.sub.y -0.416644 K.sub.x 9.042948 AR -0.167185 .times.
10.sup.-4 BR -0.223181 .times. 10.sup.-8 AP -0.350362 BP 1.21427 5
(r.sub.1) -77.812 (d.sub.1) -13.018 n.sub.1 = 1.65830 .nu..sub.1 =
53.4 Y: -62.540 A: 28.249.degree. Z: -11.013 6 (r.sub.2) 46.896
(d.sub.2) -7.184 Amount of Diopter Correction 0 D -3 D -6 D +2 D
d.sub.2 : -7.184 -7.585 -7.990 -6.906 7 (r.sub.3) -43477 (d.sub.3)
-13.915 n.sub.2 = 1.60691 .nu..sub.2 = 61.0 8 (r.sub.4) 14.861
(d.sub.4) -1.711 n.sub.3 = 1.75500 .nu..sub.3 = 27.6 9 (r.sub.5)
78.040 (d.sub.5) -1.714 10 (r.sub.6) -57.351 (d.sub.6) -6.712
n.sub.4 = 1.52154 .nu..sub.4 = 66.5 11 (r.sub.7) 48.030 (d.sub.7)
-0.500 12 (r.sub.8) -26.135 (d.sub.8) -8.719 n.sub.5 = 1.64277
.nu..sub.5 = 56.1 13 (r.sub.9) 738.733 (d.sub.9) -8.719 Amount of
Diopter Correction 0 D -3 D -6 D +2 D d.sub.9 : -8.719 -8.318
-7.913 -8.997 14 (6) .infin.(image) Y: -3.484 A: 19.864.degree. (1)
R.sub.ym /E.sub.xp .vertline. = 1.39 (2) .theta..sub.1 =
12.28.degree. (3) R.sub.y1 /R.sub.y2 = 0.55
______________________________________ Example 11 Refractive Abbe's
No. Surface Radius of Surface index (Inclination No. curvature
separation (Eccentricity) angle)
______________________________________ 1 (1) .infin.(pupil) 53.085
2 (3) R.sub.y -73.924 0.000 Y: -31.260 A: 0.000.degree. R.sub.x
-56.952 Z: 0.000 K.sub.y 0.058605 K.sub.x 0.160130 AR 0.182638
.times. 10.sup.-6 BR -0.104505 .times. 10.sup.-10 AP -0.746331 BP
-2.00536 3 (4) R.sub.y -13.612 0.000 n = 1.50290 .nu. = 68.7
R.sub.x -45.101 Y: -31.408 A: 53.699.degree. K.sub.y -1.724643 Z:
5.778 K.sub.x -1.72200 AR -0.342277 .times. 10.sup.-5 BR -0.137301
.times. 10.sup.-13 AP -1.98932 BP -0.301739 .times. 10.sup.+2 4
R.sub.y -25.089 0.000 Y: -54.154 A: 29.313.degree. R.sub.x -46.811
Z: 8.646 K.sub.y -0.530464 K.sub.x 9.488797 AR -0.171237 .times.
10.sup.-4 BR -0.258917 .times. 10.sup.-8 AP -0.347729 BP 1.27900 5
(r.sub.1) -88.462 (d.sub.1) -14.712 n.sub.4 = 1.65830 .nu..sub.1 =
53.4 Y: -62.952 A: 28.218.degree. Z: -11.834 6 (r.sub.2) 43.684
(d.sub.2) -5.446 Amount of Diopter Correction 0 D -3 D -6 D +2 D
d.sub.2 : -5.446 -7.123 -8.516 -4.296 7 (r.sub.3) -44.951 (d.sub.3)
-12.595 n.sub.2 = 1.60994 .nu..sub.2 = 60.8 8 (r.sub.4) 14.874
(d.sub.4) -2.376 n.sub.3 = 1.75327 .nu..sub.3 = 27.7 9 (r.sub.5)
51.059 (d.sub.5) -3.170 Amount of Diopter Correction 0 D -3 D -6 D
+2 D d.sub.5 : -3.170 -1.493 -0.100 -4.320 10 (r.sub.6) -61.976
(d.sub.6) -5.987 n.sub.4 = 1.50649 .nu..sub.4 = 68.3 11 (r.sub.7)
94.648 (d.sub.7) -0.500 12 (r.sub.8) -24.786 (d.sub.8) -8.420
n.sub.5 = 1.62119 .nu..sub.5 = 60.1 13 (r.sub.9) 163.122 (d.sub.9)
-8.337 14 (6) .infin.(image) Y: -3.568 A: 17.761.degree. (1)
.vertline. R.sub.ym /E.sub.xp .vertline. = 1.39 (2) .theta..sub.1 =
13.70.degree. (3) R.sub.y1 /R.sub.y2 = 0.54
______________________________________ Example 12 Refractive Abbe's
No. Surface Radius of Surface index (Inclination No. curvature
separation (Eccentricity) angle)
______________________________________ 1 (1) .infin.(pupil) 53.065
2 (3) R.sub.y -74.342 0.000 Y: -31.260 A: 0.000.degree. R.sub.x
-56.047 Z: 0.000 K.sub.y 0.109508 K.sub.x 0.074377 AR 0.152766
.times. 10.sup.-6 BR -0.816826 .times. 10.sup.-11 AP -0.768729 BP
-2.05126 3 (4) R.sub.y -13.925 0.000 n = 1.48790 .nu. = 70.4
R.sub.x -50.846 Y: -30.694 A: 58.108.degree.
K.sub.y -1.847003 Z: 6.291 K.sub.x 1.515165 AR -0.314470 .times.
10.sup.-5 BR 0.124164 .times. 10.sup.10 AP -1.99405 BP 1.19458 4
R.sub.y -26.418 0.000 Y: -58.926 A: 30.697.degree. R.sub.x -47.419
Z: 9.510 K.sub.y -0.123396 K.sub.x 9.710738 AR -0.183304 .times.
10.sup.-4 BR -0.381076 .times. 10.sup.-8 AP -0.254281 BP 1.24106 5
(r.sub.1) -101.150 (d.sub.1) -15.559 n.sub.1 = 1.65830 .nu..sub.1 =
53.4 Y: 63.452 A: 25.215.degree. Z: -9.946 6 (r.sub.2) 41.905
(d.sub.2) -5.749 7 (r.sub.3) -41.227 (d.sub.3 ) -12.741 n.sub.2 =
1.60849 .nu..sub.2 = 60.9 8 (r.sub.4) 15.255 (d.sub.4) -1.000
n.sub.3 = 1.75500 .nu..sub.3 = 27.6 9 (r.sub.5) 92.419 (d.sub.5)
-2.122 10 (r.sub.6) 44.796 (d.sub.6) -7.472 n.sub.4 = 1.53638
.nu..sub.4 = 65.7 11 (r.sub.7) 58.162 (d.sub.7) -0.500 12 (r.sub.8)
-25.005 (d.sub.8) -8.807 n.sub.5 = 1.66520 .nu..sub.5 = 52.8 13
(r.sub.9) 3628.295 (d.sub.9) -7.748 Amount of Diopter Correction 0
D -3 D -6 D +2 D d.sub.9 : -7.748 -8.409 -8.195 -8.745 14 (6)
.infin.(image) Y: -4.891 A: 20.999.degree. Amount of Diopter
Correction 0 D -3 D -6 D +2 D Y: -4.891 -2.109 -1.580 -2.947 A:
20.999.degree. 19.946.degree. 18.887.degree. 21.673.degree. (1)
.vertline.R.sub.ym /E.sub.xp .vertline. = 1.40 (2) .theta..sub.1 =
13.11.degree. (3) R.sub.y1 /R.sub.y2 = 0.53
______________________________________
Among the above-described Examples 4 to 12, Examples 8 and 12, in
which diopter correction is effected by eccentrically moving a
diopter correcting element, provide particularly favorable
correcting effect. Examples 5, 6, 8, 10 and 11, in which diopter
correction is effected without changing the pupil position 1 and
the position of the two-dimensional image display device 6, enable
the movable portion to be reduced in size. Further, since there is
no change in the overall size of the apparatus, the apparatus can
be made even more compact.
Incidentally, the visual display apparatus having the
above-described optical arrangement may be formed as a seethrough
type head-mounted visual display apparatus. FIG. 35 shows one
example of the optical arrangement of such a visual display
apparatus. The display apparatus (HMD) 63 is composed of a concave
half-mirror 3 disposed in front of each of the left and right
eyeballs 8 (in FIG. 35, the eyeball and the optical system are
illustrated for the right eye only), a shutter 18, e.g., a liquid
crystal optical element, which is disposed in front of the HMD 63,
a two-dimensional image display device 6 such as a liquid crystal
display device, and a relay optical system 5 for leading an image
of the two-dimensional image display device 6 to the concave
half-mirror 3, together with a decentered correcting optical system
4. An image (electronic image) displayed on the two-dimensional
image display device 6 is led to the concave half-mirror 3 through
the relay optical system 5 and the decentered correcting optical
system 4. The concave half-mirror 3 forms the displayed image as an
aerial enlarged image and leads it to the eyeball 8. When the
shutter 18 is open, a scene or other image in the outside world
passes through the concave half-mirror 3 and is combined with the
image displayed on the two-dimensional image display device 6 for
observation. Alternatively, the outside world image alone is
observed with the display of the electronic image turned off.
Examples of the mode of using the HMD 63 will be shown below. FIG.
36 shows one example of the mode of using the HMD 63 arranged as
shown in FIG. 35. The HMD 63 has a band 67 attached thereto so that
the HMD 63 can be fitted to the observer's head through the band
67. It should be noted that the band 67 as a support member may be
arranged such that the condition in which the HMD 63 is fastened to
the observer's head can be adjusted by using a screw or other
similar member. Alternatively, the support member may be arranged
such that a rigid head contact member is adjustably pressed on the
observer's head by the pressure of a spring or the like. It is also
possible to fasten the HMD 63 to the observer's head by using a
rubber band. Any of these arrangements may be selected
appropriately.
In addition, a headphone 68 is attached to the band 67 to enable
the user to enjoy listening to stereophonic sound in addition to
image observation. The HMD 63 having the headphone 38 is connected
with a reproducing unit 70, e.g., a portable video cassette unit,
through an image and sound transmitting cord 69. Therefore, the
user can enjoy not only observing an image but also listening to
sound with the reproducing unit 70 retained on a desired position,
e.g., a belt, as illustrated in the figure. It should be noted that
reference numeral 70a denotes a switch and volume control part of
the reproducing unit 70. Reference numerals 66a and 66b denote
image display units for the observer's right and left eyes.
FIGS. 37, 38(a) and 38(b) show other examples of the mode of using
the HMD 63. In FIG. 37, the HMD 63 incorporating the visual display
apparatus of the present invention is arranged in the form of a
helmet-type visual display apparatus. Reference numeral 68 denotes
a headphone. Although not shown, a reproducing unit (70) such as
that shown in FIG. 36 is connected to the HMD 63 through an image
and sound transmitting cord 69, as a matter of course.
FIGS. 38(a) and 38(b) show examples of the mode of using the HMD 63
in combination with a TV tuner or a video deck. FIG. 38(a) shows a
combination of the HMD 63 and a TV tuner 71, in which reference
numeral 72 denotes a TV signal receiving antenna, 73 a TV channel
selecting knob, 74 an earphone, and 75 an ON/OFF switch.
FIG. 38(b) shows a combination of the HMD 63 and a video deck 76,
in which reference numeral 77 denotes an image processing
device.
Although the visual display apparatus of the present invention has
been described above by way of some examples, it should be noted
that the present invention is not necessarily limited to these
examples, and that various changes and modifications may be
imparted thereto.
As will be clear from the foregoing description, according to the
first aspect of the present invention, it is possible to provide a
compact and lightweight visual display apparatus which enables
observation of an image that is clear throughout the image field at
a field angle of 120.degree. when the user observes with both eyes,
and which has a large exit pupil diameter.
According to the second aspect of the present invention, it is
possible to provide a visual display apparatus which provides a
wide field angle and high resolution and which enables diopter
correction to be realized simply by moving at least one of the
optical elements of the optical system of the apparatus, which is a
relatively complicated optical system.
* * * * *